Chloromycetin (chloramphenicol) is a time-tested, broad-spectrum bacteriostatic antibiotic with a well-established clinical profile. It exerts its therapeutic effect by inhibiting bacterial protein synthesis, binding to the 50S ribosomal subunit. This mechanism of action makes it effective against a wide array of Gram-positive and Gram-negative bacteria, including certain anaerobic organisms, rickettsiae, and chlamydiae. Its use is typically reserved for serious infections where other less potentially toxic antibiotics are ineffective or contraindicated, underscoring its role as a critical agent in specific therapeutic scenarios. Healthcare providers must weigh its efficacy against its potential for serious adverse effects, such as bone marrow suppression.

Features

• Active pharmaceutical ingredient: Chloramphenicol.
• Available in oral (capsules, suspension) and parenteral (intravenous) formulations.
• Bacteriostatic mechanism of action; inhibits protein synthesis at the 50S ribosomal subunit.
• Demonstrates broad-spectrum activity against a variety of susceptible organisms.
• Well-absorbed from the gastrointestinal tract with good tissue penetration, including into the cerebrospinal fluid (CSF).

Benefits

• Provides effective treatment for severe, life-threatening infections caused by susceptible organisms when other antibiotics are not suitable.
• Offers a critical therapeutic option for managing conditions like bacterial meningitis, typhoid fever, and rickettsial diseases.
• Its ability to achieve therapeutic concentrations in the CNS makes it invaluable for certain central nervous system infections.
• Serves as an alternative for patients with hypersensitivity to penicillin-class antibiotics in specific clinical contexts.
• Available in multiple formulations allows for flexible administration based on patient needs and clinical setting.

Common use

Chloromycetin is indicated for the treatment of serious infections due to organisms susceptible to its antimicrobial effects. Its use is justified only when less potentially dangerous agents are ineffective or contraindicated. Common, though serious, applications include:

• Bacterial Meningitis: Caused by Haemophilus influenzae, Neisseria meningitidis, or Streptococcus pneumoniae.
• Typhoid Fever (Salmonella typhi): Particularly in cases where the organism is susceptible and the patient cannot tolerate other agents.
• Rickettsial Diseases: Such as Rocky Mountain spotted fever, typhus, and Q fever.
• Other Severe Infections: Including brain abscesses, anaerobic infections, and certain Gram-negative bacillary infections.

Dosage and direction

Dosage must be individualized based on the severity of the infection, the susceptibility of the causative organism, and the patient’s age, weight, and hepatic/renal function. Therapeutic drug monitoring (serum concentrations) is highly recommended to maximize efficacy and minimize toxicity.

• Adults: The usual dose is 50 mg/kg/day, divided into 4 equal doses at 6-hour intervals. For severe infections (e.g., meningitis), this may be increased to 100 mg/kg/day. The total daily dose should not exceed 4 grams.
• Infants and Children: 50 to 100 mg/kg/day divided into 4 doses administered at 6-hour intervals. Dosing must be meticulously calculated and monitored due to the risk of “Gray Baby Syndrome.”
• Administration: Oral capsules should be taken with a full glass of water. The intravenous formulation must be administered by slow, intermittent or continuous infusion, prepared and diluted according to manufacturer instructions. Treatment should be continued for a minimum of 48 hours after the patient becomes asymptomatic or evidence of bacterial eradication has been obtained.

Precautions

• Hematologic Toxicity: Chloromycetin can cause serious, fatal blood dyscrasias (aplastic anemia, thrombocytopenia, granulocytopenia). These can be dose-related and reversible or idiosyncratic, irreversible, and fatal. Baseline and frequent follow-up blood counts are mandatory during therapy.
• “Gray Baby Syndrome”: A potentially fatal toxic reaction in neonates (especially premature infants) characterized by abdominal distension, cyanosis (ashen-gray color), vasomotor collapse, and irregular respiration. This is due to immature metabolic processes. Dosing in this population requires extreme caution.
• Superinfection: Use may result in overgrowth of nonsusceptible organisms, including fungi. If new infections appear during therapy, appropriate measures should be taken.
• Hepatic or Renal Impairment: Dosage reduction may be necessary in patients with impaired liver or kidney function, as these organs are responsible for metabolism and excretion.
• Prolonged Use: Avoid prolonged use; it may lead to bone marrow suppression or secondary infections.

Contraindications

Chloromycetin is contraindicated in patients with:

• A known history of hypersensitivity to chloramphenicol or any component of the formulation.
• A history of chloramphenicol-induced blood dyscrasias.
• It is not intended for the treatment of trivial infections, bacterial colds, influenza, or as prophylactic therapy.

Possible side effect

A wide range of adverse reactions, some severe, have been associated with chloramphenicol therapy.

• Hematologic: Aplastic anemia, hypoplastic anemia, thrombocytopenia, granulocytopenia.
• Gastrointestinal: Nausea, vomiting, glossitis, stomatitis, diarrhea, enterocolitis.
• Neurological: Optic neuritis, peripheral neuritis, headache, mild depression, mental confusion.
• Hypersensitivity Reactions: Fever, macular and vesicular rashes, angioedema, urticaria, anaphylaxis.
• “Gray Baby Syndrome”: (See Precautions).
• Other: Jaundice, blurred vision.

Drug interaction

Chloromycetin interacts with numerous medications, primarily due to its inhibition of hepatic cytochrome P450 enzymes.

• Anticoagulants (Warfarin): Potentiates anticoagulant effect, increasing risk of bleeding. Prothrombin time must be monitored closely.
• Hypoglycemic Agents (Tolbutamide, Chlorpropamide): May enhance hypoglycemic effect.
• Phenytoin, Phenobarbital: Chloramphenicol may increase serum levels of these drugs, leading to toxicity. Conversely, these drugs may decrease chloramphenicol levels.
• Vitamin B12: May antagonize the hematinic response to vitamin B12.
• Penicillins, Cephalosporins: Chloramphenicol, being bacteriostatic, may antagonize the bactericidal effect of these drugs in some situations.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should not double the dose to “catch up.” Maintaining a consistent dosing schedule is crucial for maintaining effective serum concentrations.

Overdose

Overdose can be fatal, primarily due to cardiovascular collapse and bone marrow toxicity.

• Symptoms: Nausea, vomiting, unpleasant taste, diarrhea, gray syndrome in infants (pallor, cyanosis, vasomotor collapse, metabolic acidosis, death).
• Treatment: There is no specific antidote. Treatment is supportive and symptomatic. Gastric lavage may be indicated if ingestion was recent. Hemodialysis or charcoal hemoperfusion may be of limited value. Intensive supportive care, including management of cardiovascular and respiratory status, is essential.

Storage

• Store at room temperature (20°C to 25°C or 68°F to 77°F), away from light, moisture, and heat.
• Keep the container tightly closed.
• Do not store in the bathroom.
• Keep all medications out of the reach of children and pets.
• Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed.

Disclaimer

This information is for educational and informational purposes only and does not constitute medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here. The use of Chloromycetin must be under the direct supervision of a qualified healthcare professional due to its potential for severe and life-threatening side effects.

Reviews

• Infectious Disease Specialist, 15 years experience: “Chloromycetin remains a powerful tool in our arsenal for multidrug-resistant typhoid and certain CNS infections. Its utility is undeniable, but it demands immense respect. We never prescribe it without a clear, definitive indication and rigorous hematological monitoring. It’s a drug you use when you have no better options, and it has saved lives in those precise scenarios.”
• Clinical Pharmacist: “Managing a patient on chloramphenicol is a high-alert situation. The pharmacokinetics are unpredictable, and the therapeutic window is narrow. It’s the textbook example of a drug where therapeutic drug monitoring is not just recommended, it’s essential for safe use. The interactions are significant and must be managed proactively.”
• Pediatric Intensivist: “The specter of ‘Gray Baby Syndrome’ means we approach this drug with extreme caution in the NICU and PICU. It is reserved for the most dire circumstances where no alternative exists. When used correctly with weight-based dosing and constant monitoring, it can be effective, but the margin for error is virtually zero.”